Bottom hole assembly for fluid operated pump system with tensioning means therein



April 30, 1968 R. F. MCARTHUR ETAL 3,380,760

BOTTOM HOLE ASSEMBLY FOR FLUID OPERATED PUMP SYSTEM WITH TENSIONING MEANS THEREIN Original Filed June 8, 1959 4 Sheets-Sheet 1 ,H5/vers, /Ecf, .gassen @Kee/M April 30, 1968 R. F. MGARTHUR ETAL 3,380,750

BOTTOM HOLE ASSEMBLY FOR FLUID OPERATED PUMP SYSTEM WITH TENSIONING MEANS THEREIN Original Filed June 8, 1959 4 Sheets-Sheet 2 I FW; M

April 30, 1968 R. F. MGARTHUR ETAL 3,380,760

BOTTOM HOLE ASSEMBLY FOR FLUID OPERTED PUMP SYSTEM WITH TENSIONING MEANS THEREIN Original Filed June 8, 1959 4 Sheets-Sheet 5 ,nue-Armas MSgQn/w?,

Eras/KE@ APH] 30, 1968 R. F. MGARTHUR ETAL 3,389,760

BOTTOM HOLE ASSEMBLY FOR FLUID OPERTED PUMP SYSTEM D WITH TENSIONING MEANS THEREIN 4 Sheets-Sheet 4 Original Filed June 8 @AAW/Aw? United States Patent O 3,380,760 BOITOM HOLE ASSEMBLY FOR FLUID SPER- ATED PUMP SYSTEM WITH TENSEONING MEANS THEREIN Ralph F. McArthur, Huntington Park, and Mathew R. Mecuslrer, La Habra, Calif., assignors to Kobe, Inc., Huntington Park, Calif., a corporation of California Application Aug. 3, 1962, Ser. No. 214,635, now Patent No. 3,182,598, dated May 11, 1965, which is a division of application Ser. No. 818,870, June 8, 1959, now Patent No. 3,078,804, dated Feb. 26, 1963. Divided and this application Apr. 6, 1965, Ser. No. 445,962

4 Claims. (Cl. 285 32) This application is a division of our co-pending application Ser. No. 214,635, iiled Aug. 3, 1962, now Patent No, 3,182,598, issued May 11, 1965, which, in turn, is a division of our application Ser. No. 818,870, filed June 8, 1959, now Patent No. 3,078,804, issued Feb. 26, 1963.

The present invention relates to a duid-operated oilwell pump system comprising a bottom hole assembly or housing adapted to receive therein an elongated, fluidoperateted pump assembly of the reciprocating type having an engine or motor means which is actuable by an operating Huid, such as oil under high pressure to operate a pump means for pumping production uid to the surface. More particularly, the bottom hole housing comprises an assembly of relatively large tubes and smaller pipes interconnected in parallel, i,e., side-by-side, relation by suitable ttings, such as sealing collars and a bottom shoe, the relatively large tubes receiving the fluid-operated pump assembly therein, and the smaller pipes serving as a uid conductor subject at least to an internal pressure due to a uid column extending upwardly in the well to the surface.

A general object of the invention is to provide a bottom hole housing of the foregoing nature incorporating means for facilitating the assembly of the various components in their proper relative positions.

More speciiically, an important object of the invention is to provide means for assembling the vaiious components with threaded connections between the fittings and the parallel tubes and pipes.

Another important object is to provide means for tensioning the smaller pipes to offset fluid pressure end loads on the ttings due to a fluid pressure in such pipes, thereby relieving the larger tubes of such loads.

The foregoing objects of the present invention, together with various other objects thereof which will be evident to those skilled in the huid-operated pump art, may oe achieved with the exemplary embodiment of the invention described in detail hereinafter and illustrated in the accompanying drawings, in which:

PIG. 1 is a vertical sectional View illustrating diagrammatically a huid-operated pump system which embodies the invention as installed in a well, this pump system being illustrated in specific detail throughout the remainder of the drawings;

FIG. 2 is a vertical sectional View of the upper end of the fluid-operated pump system of the invention shown in specilic detail, and is taken as indicated by the arrowed line 2-2 of FIG. 7;

FIG. 3 is a vertical sectional view of a portion of the pump system below that illustrated in FIG. 2 and is taken along the arrowed line 3 3 of FIG. 8;

FIG. 4 is a vertical sectional view of a portion of the Patented pr. 30, 1968 rice pump system below that illustrated in FIG. 3 and is taken as indicated by the arrowed line 4 4 of FIG. 9;

FIG. 5 is a vertical sectional View of a portion of the pump system below that of FIG. 4;

FIG. 6 is a vertical sectional view of the lower end of the pump system;

FIGS. 7, 8 and 9 are horizontal sectional views respectively taken along the arrowed lines 7 7, 8 8 and 9 9 of FIGS. 2, 3 and 4, respectively; and

FIGS. 10 and 11 are enlarged, fragmentary vertical sectional views illustrating seal loading means of the invention in more detail.

Referring particularly to FIG. 1 of the drawings, the fluid-operated pump system of the invention includes a bottom hole assembly which provides a housing means for receiving and housing in an operative position therein a free, fluid-operated pump assembly 22. The bottom hole assembly 20 is suspended in a well casing 24 provided at its lower end with a perforated liner 26, shown as integral with the casing, through which production fluid from a surrounding productive formation 28 may enter the well. The suspension means for the bottom hole assembly 20 comprises a tubing system which includes a pump tubing 30 that acts as a supply tubing for `delivering an operating iluid under pressure to the pump assembly 22 when it is in its operative position in the bottom hole assembly, a return tubing 32 for conveying spent operating fluid from the pump assembly to the surface, and a production tubing 34 for conveying to the surface production fluid from the well which is discharged by the pump assembly. The free pump assembly 22 is hydraulically movable between its operative position in the bottom hole assembly 20 and the surface through the supply tubing 30 in the construction illustrated.

It will be understood that while a separate return tubing 32 for the spent operating fluid has been disclosed, thereby providing a closed operating fluid system, the spent operating fluid may be mixed with the production uid and returned via the production tubing 34, thereby providing an open operating uid system.

Considering the bottom hole assembly 20 in a general way, and primarily with reference to FIG. l of the drawings, it includes an upper sealing collar 36 to which the lower ends of the supply and return tubings 30 and 32 are connected. As will be described in more detail hereinafter, the upper sealing collar 36 provides an operating uid exhaust passage means 38 which conveys spent operating uid from the pump assembly 22 to the return tubing 32.

Connected to the lower end of the upper sealing collar 36 is the upper end of a motor housing tube 40 to the lower end of which is connected an upper intermediate sealing collar 42. The lower end of the production tubing 34 is connected to the sealing collar 42 and this sealing collar is provided with a branch outlet passage means 44 which conveys production fluid discharged by the pump assembly 22 to a main outlet passage means 46 for production uid which leads to the lower end of the production tubing 34.

Connected to the lower end of the upper intermediate sealing collar 42 is the upper end of an upper pump housing tube 48 to the lower end of which is connected a lower intermediate sealing collar 50 having therein a branch outlet passage means 52 which conveys production uid discharged by the pump assembly 22 to the main outlet passage means 46.

The lower end of the lower intermediate sealing collar 50 has connected thereto the upper end of a lower pump housing tube 54 and connected to the lower end of this tube is a lower sealing collar 55 having a bottom shoe 56 connected thereto. Formed in the bottom shoe 56 is a branch outlet passage means 58 which conveys production fluid discharged by the pump assembly 22 to the main outlet passage means 46.

The supply tubing 30, the sealing collars 36, 42, 50 and 55, the motor housing tube 40, the pump housing tubes 48 and 54, and the bottom shoe 56 are all axially, i.e., vertically, aligned and provide a housing or housing means for the pump assembly 22, the latter being movable between the surface and an operative position within the bottom hole assembly through the supply tubing. The bottom shoe 56 is provided therein with an annular seat 60 for 'a standing valve assembly 62 on which the lower end of the pump assembly 22 is seated when the pump assembly is in its operative position in the bottom hole assembly.

The standing valve assembly communicates with the interior of the perforated liner 26 and constitutes the lower end of a production huid inlet passage means 64 for conveying production fluid from the well to the pump assembly 22 vfor pumping into the main outlet passage means 46 by way of the branch outlet passage means 44, 52 and 5S. The inlet passage means 64 includes, generally, an inlet passage 6.6 formed in an inlet plug 68 and a lower sealing adapter 154 of the pump assembly 22, the inlet plug forming the lower end of the pump assembly and being seated on the standing valve assembly 62 when the pump assembly is in its operative position in the bottom hole assembly 20. The inlet passage means 64 also includes a lower annular passage 70 the lower end of which communicates with the inlet passage 66, the lower annular passage 70 having outer and inner walls respectively formed by the bottom hole and pump assemblies 20 and 22 and extending from within the sealing collar 55 upwardly through the lower pump housing tube 54 into the lower intermediate sealing collar 50. The inlet passage means 64 further includes an upper annular passage 72 the lower end of which is connected to the upper end of the lower annular passage 70 by a bypass passage 74 formed in the lower intermediate sealing collar 50, the upper annular passage 72 having outer and inner walls respectively formed by the bottom hole and pump assemblies 20 and 22 and extending upwardly from within the lower intermediate sealing collar 50 through the upper pump housing tube 48 into the upper intermediate sealing collar 42.

It will be noted that, with the exception of the inlet passage 66 of the inlet passage means 64, all of the components or portions of the production fluid inlet passage means 64 and the production fluid outlet passage means 44, 46, 52 and 58 are located within the bottom hole assembly 20 externally of the pump assembly 22 so that they do not occupy any space within the pump assembly which would tend to reduce the displacement thereof. Since the inlet passage 66 is formed in the inlet plug 68 at the lower end of the pump assembly 22, it has no effect on the displacement of the pump assembly.

Similar considerations are applicable to the handling of the operating fluid under pressure for actuating the pump assembly 22 and the spent operating uid discharged by the pump assembly, the high pressure operating fluid and the low pressure spent operating fluid being handled in passages within the bottom hole assembly 20 externally of the pump assembly 22 wherever necessary to avoid a tendency to reduce the displacement of the pump assembly with respect to the operating fluid. In this connection, it will be noted that the operating iluid exhaust passage means 38 is formed in the upper sealing collar 36 externally of the pump assembly 22. With this same objective in mind, the bottom hole assembly 20 provides an annular operating lluid passage 76 which ex- 4 tends from within the upper sealing collar 36 downwardly through the motor housing tube 40 into the upper intermediate sealing collar 42, the outer and inner walls of this annular passage also being formed by the bottom hole and pump assemblies 20 and 22, respectively, so that such passage is also located entirely externally of the pump assembly. The function of the annular operating fluid passage 76 will be brought out hereinafter.

Considering the pump assembly 22 in detail now, it includes at its upper end a packer nose assembly 78 comprising a tubular packer mandrel 80 having thereon downwardly facing packer cups 82 which make uid tight seals with the supply tubing 30 when fluid pressure is applied therebeneath, whereby the pump assembly may be moved upwardly through the supply tubing to the surface hydraulically in a manner to be described. The packer mandrel 80 is provided therein with ports forming an operating fluid intake 84 lfor admitting operating fluid under pressure from the supply tubing 30 into the pump assembly 22.

The lower end of the packer mandrel 80 is connected to an upper sealing adapter 86 which registers with the upper sealing collar 36 when the pump assembly 22 is in its operative position. The upper sealing adapter 86 is provided therein with ports forming an operating fluid exhaust S8 which communicates with the exhaust passage means 38 in the upper sealing collar 36 when the pump assembly 22 is in its operative position. The operating uid exhaust 88 and the exhaust passage means 38 are isolated by elastomeric annular seals 90 and 92 carried by the upper scaling adapter 86 respectively above and below the operating iluid exhaust 88 and engageable with the upper sealing collar 36.

Connected to the lower end of the upper sealing adapter 86 is a fluid operated engine or motor section 94 of the pump assembly 22, the lower end of the motor section being connected to an upper intermediate sealing adapter 96 which is disposed within the upper intermediate sealing collar 42 when the pump assembly 22 is in its operative position. The annular operating fluid passage 76 within the motor housing tube 40 encircles the motor section 94 of the pump assembly 22 and is isolated by the seal 92 on the upper sealing adapter S6 and by an elastomeric annular seal 98 on the sealing adapter 96 and engageable with the sealing collar 42.

The lluid operated motor section 94 of the pump assembly 22 includes a motor cylinder 100 formed by a motor cylinder barrel or tube 101 and having therein a motor piston 102 which is reciprocated in the motor cylinder by connecting the upper and lower ends of the motor cylinder iirst to the operating fluid intake and exhaust 84 and S8, respectively, and then to the operating iluid exhaust and intake 88 and 84, respectively, in an alternating manner. In other words, the connections between the upper and lower ends of the motor cylinder and the operating fluid intake and exhaust 84 and 8S are alternately reversed, thereby applying to the motor piston 102 an alternating lluid pressure force differential which reciprocates it in its cylinder.

The foregoing eltect is achieved by an engine or motor valve 104, FIG. 2, forming part of the motor section 94 of the pump assembly 22 and communicating with the operating fluid intake and exhaust 84 and 8S. The engine valve 104 is conventional and may, for example, be of the type disclosed in Patent No. 2,311,157, granted Feb. 16, 1943, to Clarence l. Coberly. Consequently, it is unnecessary to consider the engine valve 104 in detail herein, it being sufcient to point out that it includes a fluid operated valve member 106 slidable vertically in a valve body 108 and controlled by a valve rod 110 connected to the motor piston 102. The valve body 108 connects the upper end of the motor cylinder barrel 101 to the upper sealing adapter 86 as shown in FIG. 2, the lower end of the motor cylinder lbarrel being connected to the upper intermediate sealing adapter 96, as shown in FIG. 3.

The motor section 94 of the pump assembly 22 is provided with two operating fluid passage means 112 and 114 respectively connecting the engine valve 104 to the upper and lower ends of the motor cylinder 100, the two passage means mentioned providing the communication between the engine valve and the upper and lower ends of the motor cylinder which is necessary to permit the engine valve to apply to the motor piston 102 the alternating fluid pressure force differential discussed previously. As shown in FIG. 2, the operating Huid passage means 112 establishing communication between the engine valve 104 and the upper end of the motor cylinder 100 includes suitable passages, ports and the like in the engine valve body 108 and in a tubular tting assembly 116 disposed in the upper end of the motor cylinder barrel 101 adjacent the engine valve 104. The passages, ports and the like forming the operating uid passage means 112 are clearly shown in FIG. 2 of the drawings and it is therefore thought unnecessary to describe them in detail.

The operating uid passage means 114 connecting the engine valve 104 to the lower end of the motor cylinder 100 includes the annular operating fluid passage 76 described previously. The upper end of the annular passage 76 communicates with ports 118 which, in turn, communicate with the engine valve 104 through suitable passages, ports, and the like formed in the iitting assembly 116 and the engine valve body 118 and adequately illustrated in FIG. 2 of the drawings so that describing them in detail is unnecessary. The ports 118 are formed in the upper end of the barrel or tube 101 forming the motor cylinder 100 and are prevented from communicating with the upper end of the motor cylinder proper by the fitting assembly 116. The lower end of the annular passage 76 communicates with ports 120 formed in the lower end of the barrel 101 and communicating with the lower end of the motor cylinder 100 below the motor piston 102 through suitable ports, passages, and the like formed in the upper intermedite sealing adapter 96 and clearly illustrated in FIG. 3 of the drawings.

The pump means o'E the pump assembly 22 includes in the construction illustrated upper and lower double-acting pump sections 122 and 124 respectively disposed in the upper and lower pump housing tubes 4S and 54 when the pump assembly 22 is in its operative position. The upper and lower pump sections 122 and 124 respectively include upper and lower pump cylinders 126 and 128 respectively formed by upper and lower pump cylinder barrels or tubes 130 and 132. Resectively reciprocable in the upper and lower pump cylinders 126 and 128 are upper and lower pump pistons 134 and 136, the upper pump piston 134 being connected to the motor piston 102 by a rod 138, FIGS. 3 and 4, and the two pump pistons being interconnected by a rod 140, FIGS. 4 and 5. Connected to the lower pump piston 136 and extending downwardly therebelow into a balance tube 142, FIGS. 5 and 6, is a lower rod 144. The cross sectional area of the lower rod 144 is the same as that of the valve rod 110, and the rods 110, 138, 140 and 144 and the pistons 102, 134 and 136 are all tubular so that the iiuid pressure acting downwardly on the valve rod is also present in the balance tube 142 to act upwardly on the lower rod 144. Thus, the piston and rod assembly is hydraulically balanced with respect to the fluid pressure acting downwardly on the valve rod 110, which fluid pressure is the operating uid pressure in the supply tubing 30, being applied to the upper end Of the valve rod 110 through the packer mandrel 80, an axial passage 146, FIG. 2, in the upper sealing adapted 86 and the interior of the engine valve member 166.

Considering the pump means of the pump assembly 22 in more detail, the upper pump cylinder barrel 130 is connected to the lower end of the upper intermediate sealing adapter 96, FIG. 3, and the lower end of this barrel is connected to the upper end of a lower intermediate sealing adapter 148, FIG. 4. The upper end of the lower pump cylinder barrel 132 is connected to the lower end of the lower intermediate sealing adapter 14S, FIG. 4, and the lower end of the lower pump cylinder barrel is connected to a fitting 150, as shown in FIG. 5. The balance tube 142 mentioned previously is connected to the lower end lof the tting and a barrel or tube 152 surrounding the balance tube 142 connects the fitting 150 to the lower sealing adapter 154, which is disposed within the lower sealing collar 55 when the pump assembly 22 is in its operative position. The inlet plug 68 at the lower end of the pump assembly is connected to the lower sealing adapter 154.

Since the upper and lower pump sections 122 and 124 are double acting as previously stated, each is provided with two vertically spaced production uid inlets. The upper and lower production fluid inlets of the upper pump section 122 are designated by the numerals 156 and 158, respectively, and the upper and lower production fluid inlets of the lower `pump section 124 are designated by the numerals and 162, respectively. The production duid inlets 156 and 158 for `the upper pump section 122 communicate with the upper annular passage 72 of the production yfluid inlet passage means 64, while the production uid inlets 160 and 162 of the lower pump section 124 communicate with the lower annular passage 70 of the production uid inlet passage means 64.

The upper annular production inlet passage 72 is lisolated, so that it communicates only with that portion ofthe exterior of the upper pump section 122 having the production fluid inlets 156 and 158 therein, by elastomeric annular seals 164 and 166 respectively carried by the upper and lower intermediate sealing adapters 96 and 14S. Similarly, the lower annular production fluid inlet passage 7 0 is isolated, so that it communicates only with that portion of the exterior of the lower pump section 124 having the production fiuid inlets 160 and 162 therein, by elastomeric annular seals 168 and 170 respectively carried by the lower intermediate and the lower sealing adapters 14S and 154.

As shown in FIG. 3, the upper production fluid inlet 156 of the upper pump section 122, which inlet is shown as comprising circumferentially spaced ports, is formed in the upper end of the upper pump cylinder barrel 130 and communicates with the upper end of the upper pump cylinder 126 through a suitable inlet check valve means 172 carried by the upper intermediate sealing adapter 96. The inlet check valve means 172 includes suitable passages, ports, and the like in the upper intermediate sealing adapter 96 which it is thought unnecessary to describe specifically, these being clearly shown in FIG. 3 of the drawings. Similarly, the lower production fluid inlet 158 of the upper pump section 122 is formed in the lower end of the upper pump cylinder barrel 130 and communicates with the lower end of the upper pump cylinder 126 through a suitable inlet check valve means 174 carried by the lower intermediate sealing adapter 148, as shown in FIG. 4 of the drawings. Again similarly, the upper and lower production uid inlets 160 and 162 of the lower pump section 124 are formed in the upper and lower ends of the lower pump cylinder barrel 132, as shown in FIGS. 4 and 5, respectively, and respectively communicate with the upper and lower ends of the lower pump cylinder 128 through suitable upper and lower inlet check valve means 176 and 178 respectively carried by the lower intermediate sealing adapter 148 and the fitting 150.

The foregoing completes the description of the manner in which production fluid from the well is admitted into the upper and lower ends of the upper and lower pump sections 122 and 124 and the manner in which the production fluid is discharged therefrom into the main outlet passage means 46 through the branch outlet passage means 44, 52 and 58 will now be described.

The upper intermediate sealing adapter 96 is provided between the seals 98 and 164 thereon with ports forming a production fluid outlet 180 for the upper end of the upper pump section 122, this outlet registering with the branch outlet passage means 44 when the pump yassembly 22 is in its operative position in the bottom hole assembly 28. As shown in FIG. 3 of -the drawings, the upper intermediate sealing adapter 96 carries an outlet check valve means 182 through which production fluid discharged from the upper end of the upper pump cylinder 126 ows to the production uid outlet 180 by way of suitable ports, passages, and the like in the sealing adapter in question, these being clearly shown in FIG. 3 so that a further description is unnecessary. Similarly, the branch outlet passage means 44 with which the production fluid outlet 180 registers includes a collection of annular grooves, ports, and the like in the upper intermediate sealing collar 42 which are clearly shown in FIG. 3 so that a further description is not required,

Disposed between the seals 166 and 168 on the lower intermediate sealing adapter 148 is a production iiuid outlet 184 comprising circumferentially spaced po-rts formed in the sealing adapter 148 and registering with the branch outlet passage means 52 in the lower intermediate sealing collar 50 when the pump assembly 22 is in its operative position. As shown in FIG. 4 of the drawings, the branch outlet passage means 52 comprises a collection of grooves, ports, and the like in the lower intermediate sealing collar 50 which it is unnecessary to describe specifically. The production uid outlet 184 serves the lower end of the upper 'pump section 122 and the upper end of the lower pump section 124, the production fluid outlet 184 communicating with the lower end of the upper pump cylinder 126 through an outlet check valve means 186 and communicating with the u-pper end of the lower pump cylinder 128 through an outlet check valve means 188, the two outlet check valve means just mentioned being carried by the lower intermediate sealing adapter 148. Communication between the lower end of the upper pump cylinder 126 and the production fluid outlet 184 through the outlet check valve means 186 and communication between the upper end of the lower pump cylinder 128 and the production uid outlet 184 through the outlet check valve means 188 are established by suitable ports, passages, and the like in the lower intermediate sealing adapter 148, these being clearly shown in FIG. 4 of the drawings so that a further -description is not needed. Sim-ilarly, the branch outlet passage means 52 with which the production iiuid outlet 184 communicates when the pump assembly 22 is in its operative position is formed by suitable grooves, ports, and the like in ythe lower intermediate sealing collar 50 which are also clearly shown in FIG. 4 so that they need not be described in detail.

The lower end of the lower pump section 124 discharges production uid through an outlet check valve means 190, FIG. 5, carried by the tting 150, this fitting being provided with suitable ports, passages, and the like, which, as shown in FIG. 5, connect the lower end of the lower pump cylinder 128 to the annular space between the balance tube 142 and the tube 152 which connects the fitting 150 to the lower sealing adapter 154. As shown in FIG. 6, the lower sealing adapter 154 is provided with suitable passages, ports, and the like which convey the production fluid discharged by the lower end of the lower pump section 124 to a production uid outlet 192 formed by circumferentially spaced ports in the lower sealing adapter below the seal 170. As FIG. 6 clearly shows, the production fluid discharged by the lower end of the lower pump section 124 ilows downwardly around the inlet plug 68 and then through the branch outlet passage means 58 in the bottom shoe 56 into the main outlet passage means 46.

The pump assembly 22 is run into and out of the well hydraulically in the usual manner for pump assemblies of this type. Brietly, the pump assembly 22 is run in from the surface into its operative position in the bottom hole assembly by introducing iluid into the supply tubing 39 above the pump assembly at a pressure suicient to move the pump assembly downwardly into its operative position. To run the pump assembly 22 out, fluid is introduced into the upper end of the production tubing 34, whereby the fluid in the production tubing and in the main outlet passage means 46 enters the pump-assembly housing provided by the bottom hole assembly 20 below the pump assembly 22 by way of the branch outlet passage means 58 in the bottom shoe 56, as shown in FIG. 6 of the drawings. Initially, upward pressure is applied to an annular area of the inlet plug 68 equal to the cross sectional area of the pump assembly 22 minus the area of engagement between the inlet plug 68 and the standing valve assembly 62. As soon as the pump assembly 22 unseats from the standing valve assembly 62, whereupon the standing valve closes, the upward pressure applied to the production tubing 34 acts on the entire cross sectional area of the pump assembly to move it upwardly. Until such time as the lowermost seal disengages the lower sealing collar 55, it prevents bypassing of the fluid introduced through the production tubing 34 past the pump assembly. Thereafter, the packer cups 82 at the upper end of the pump assembly 22 prevent bypassing so that the pump assembly is hydraulically lifted to the surface.

Each of the various external annular seals 9i), 92, 9S, 164, 166, 168 and 176 carried by the pump assembly 22 is loaded in the vertical or axial direction when the pump assembly is in its operative position to such an extent that it will not expand and contract excessively as the pressure of one or the other of the fluids which it separates decreases and increases, respectively. In order to minimize such expansion and contraction of the seals in question, they are pressurized or loaded to an extent of at least the same order of magnitude as the differences between the pressures of the fluids which they separate, and preferably higher. The resultant minimizing of expansion and contraction of each of the seals mentioned as the pressure of one or the other of the fluids separated thereby decreases and increases minimizes internal friction within the seal, and thus prevents the heat generation which such internal friction would produce, the net effect being a very marked increase in the service life of the seal. Without such loading or pressurization, the external seals on the pump assembly which separate fluids having variable pressure diierentials therebetween would burn out in a very short period of time from the heat generated by internal friction as they expand and contract.

Further, since the foregoing loading or pressurization of each of the seals 90, 92, 98, 164, 166, 168 and 170 is in the axial direction, it results in squeezing such seal outwardly into sealing engagement with the corresponding component of the bottom hole assembly 20 only when the pump assembly 22 is in its operative position. Thus, it is not necessary to subject the seals in question to initial squeezes, which means that their external diameters are less than the external diameters of the sealing adapters of the pump assembly as the latter is run into or out of the well. Consequently, the external seals on the pump assembly cannot be abraded by the supply tubing 30 and the bottom hole assembly 20 as the pump assembly is run in or out.

The Various external seals 90, 92, 98, 164, 166, 168 and 170 are pressurized or loaded in similar fashions so that it is necessary to consider how this is accomplished in connection with only a couple of the seals, e.g., the seals 98 and 164, for purposes of illustration. The manners in which the seals 98 and 164 are pressurized when the pump assembly 22 is in its operative position; are shown in FIGS. l0 and ll, respectively, these figures duplicating portions of FIG. 3 on an enlarged scale.

Considering the seal 98 rst, it encircles a reduced diameter portion 194 of the upper intermediate sealing adapter 96 and is engageable with a liner 196 forming part of the upper intermediate sealing colla1 42. The seal 98 is disposed between a lower rigid sleeve 198, which encircles the reduced diameter portion 194 of the sealing adapter 96 and which is engageable with an annular shoulder 200 thereon, and an upper rigid, differential area sleeve 202 which is axially slidable on the reduced diameter portion 194 of the sealing adapter 96 and on a further. reduced diameter portion 204 thereof, an O-ring 206 maintaining a uid tight seal between the sleeve 202 and the portion 204 of the sealing adapter 96. The sleeve 202 has a small-area lower end 203 engageable with the seal 9S and a large-area upper end 210, this sleeve also having an internal annular surface 212 the area of which is equal to the difference between the cross sectional areas of the portions 194 and 204 of the sealing adapter 96, and thus to the dierence between the areas of the upper and lower ends 210 and S of the sleeve.

The upper end 210 of the sleeve 202 is exposed to the pressure in the annular operating uid passage Fi6 through the slight annular clearance, not shown, which is necessarily present between the motor cylinder barrel 101 and the liner 196 of the upper intermediate sealing collar 42, the pressure in the annular operating uid passage 76 being alternately the operating fluid pressure in the supply tubing and the spent operating tluid pressure in the return tubing 32. The annular surface 212 of the sleeve 202 is exposed to the production iuid inlet pressure through one or more ports and passages 214 and 216 in the upper intermediate sealing adapter 96, the passage or passages 216 communicating with the production huid inlet 156 in the manner shown in FIG. 3 of the drawings.

It will be apparent from the foregoing that the sleeve 202 is a differential area sleeve having either the pressure of the operating fiuid in the supply tubing 30, or the pressure of the spent operating iiuid in the return tubing 32, applied to the upper end 210 thereof and having the much lower production uid inlet pressure applied to the annular surface 212 thereof. The pressures acting on the upper end 210 of the sleeve 202 and the pressure acting on the annular surface 212 thereof produce an axial force which axially compresses the seal 98 and which is equal to the area of the annular surface 212 multiplied by the difference between the production fluid inlet pressure and either the pressure of the operating fluid in the supply tubing 30, or the pressure of the spent operating iiuid in the return tubing 32. In either event, the pressure applied to the seal 98 exceeds the difference between the pressures which this seal separates, the pressure below the seal 93 being the pressure of the production uid column in the production tubing 34, and the pressure above this seal being either the pressure of the spent operating iuid column in the return tubing 32, which is the same as the pressure of the production uid column in the production tubing if the densities of the operating and production uids are the same, or the pressure of the operating fluid in the supply tubing 30. Consequently, as the pressure above the seal 98 alternates between the pressure in the supply tubing 30 and the pressure of the spent operating uid column in the return tubing 32, the seal cannot expand and contract excessively and thus cannot generate excessive heat by internal friction so that its service life is materially extended.

Referring to FIG. 11 of the drawings, encircling the sealing adapter 96 is a band 220 which, in turn, is encircled by the seal 164, the latter being engageable with the liner 196 of the sealing collar 42. The seal 164 is disposed between a sleeve 222, which encircles the band 220 and which is seated on the upper end of the upper pump cylinder barrel 130, and a dilerential area sleeve 224 slidably engaging the band 220 and the sealing adapter 96. The sleeve 224 has a small-area lower end 226 engaging the seal 164 and a large-area upper area 223 exposed to the production uid discharge pressure in the branch outlet passage means 44, this sleeve being sealed internally relative to the sealing adapter 96 by an O-ring 230. The differential area sleeve 224 is also provided with an internal annual surface 232 facing in the opposite direction from the upper end 228 thereof and having an area equal to the difference between the areas of the upper and lower ends 223 and 226. As will be apparent, the

band 220 effectively increases the diameter of a portion of the sealing adapter 96 to provide the differential area between the upper and lower ends 228 and 226 of the sleeve 224.

As previously stated, the upper end 228 of the sleeve 224 is exposed to the production fluid outlet pressure in the branch outlet passage means 44. The annular surface 232 is exposed to the production fluid inlet pressure in the upper annular inlet passage 72, as will be apparent from FIG. 3, through clearances, not shown, inherently present between the liner 196 and the upper pump cylinder barrel 130, between the upper pump cylinder barrel and the sleeve 222 and the band 220 and between the sealing adapter 96 and the band 200. Consequently, the production fluid discharge pressure acting on the upper end 22S of the sleeve 224 and the production fluid inlet pressure acting on the annular surface 232 thereof result in the application of a pressure to the seal 164 equal to the area of the annular surface 232 multiplied by the difference between the production fluid discharge pressure and the production uid inlet pressure. Thus, the seal 164 is subjected to a pressure at least equal to the difference between the pressures of the fluids which it separates.

The seals 166, 168 and 170 are pressurized in much the same manner as the seal 164, utilizing the difference between the production fluid discharge pressure and the production fluid inlet pressure. Consequently, a further description is unnecessary.

The seal at the upper end of the pump assembly 22 is pressurized in much the same manner as the seal 98, except that the difference between the operating fluid pressure in the supply tubing 30 and the pressure of the spent operating uid in the return tubing 32 is utilized, as will be apparent from FG. 2 of the drawings. Briefly, the seal 9i) is pressurized by a differential area sleeve 234 having its upper end 236 exposed to the operating iiuid pressure in the supply tubing 30 and having a smaller, downwardly facing annular surface 238 exposed to the return iluid pressure in the operating fluid exhaust 88 through one or more ports and passages 240 and 242. The action of the sleeve 234 on the seal 90 is very similar to that of the sleeve 242 on the seal 98 so that a further description is not required. The pressure applied to the seal 90 by the sleeve 2.34 in this fashion is transmitted to the seal 92 mechanically 'by sleeves 244, 246 and 248 slidable on the upper sealing adapter 86, the sleeve 246 having the operating fluid exhaust 8S formed therein.

Thus, when the pump assembly 22 is in its operative position and is in operation, all of the external seals thereon are pressurized to urge them into sealing engagement with the corresponding components of the bottom hole assembly 20, and to prevent them from expanding and contracting so that the resultant detrimental effect of heat generation due to internal friction is avoided. Further, all of the seals which separate the clean operating fluid from the possibly contaminated production fluid, viz., the seals 9S, 164, 166, 168 and 170, are pressurized when the pump assembly 22 is in its operative position with the standing valve 62 open, even if the pump is shut down. Thus, the operating fluid cannot become contaminated. When the pump assembly 22 is being run in or out, the external seals are retracted into the grooves formed by the sleeves which receive them therebetween so that the seals cannot be abraded by contact with the bottom hole assembly 20, or the supply tubing 30.

Preferably, the annular seals 90, 92, 9S, 164, 166, 168 and 170 have steel cores to insure outside diameter accuracy and to resist blowing out of their grooves.

Turning now to a consideration of the present invention, the main outlet passage means 46 paralleling the pump assembly 22 includes a pipe 250 interconnecting the upper and lower intermediate sealing collars 42 and 50 and a pipe 252 interconnecting the lower intermediate sealing collar 50 and the bottom shoe 56. Interconnecting the upper and lower intermediate Isealing collars 42 and 50 by means of the upper pump housing tube 4S and assays-u l l the pipe 250, and interconnecting the lower intermediate sealing collar 50 and the bottom shoe 56 by means of the lower pump housing tube 54 and the pipe 252, presents certain problems which are considered hereinafter and which the present invention overcomes in the manner set forth hereinafter. For convenience, the consideration of this aspect of the invention will be restricted to interconnecting the lower intermediate sealing collar G and the bottom shoe 56 with the lower pump housing tube 54 and the pipe 252, with the understanding that the discussion also applies to interconnecting other components of the bottom hole assembly 20.

Referring to FIGS. 4, 5 and 6 of the drawings, it will be noted that the pump housing tube 54 is threaded into the lower sealing collar 55 by means of ordinary tapered pipe threads. Consequently, once the lower end of the pump housing tube 54 is threaded all the way into the sealing collar 55, no further relative rotation of these parts is possible. However, it is necessary to provide relatively unrestricted rotation between the bottom shoe 56 and the sealing collar 50 at some point to permit alignment of the portions of the sealing collar 50 and the bottom shoe 56 into which the parallel pipe 252 is threaded in the manner shown in FGS. 4 to 6 of the drawings, and to space the sealing collar 50 and the bottom shoe accurately. For this purpose, the upper end of the pump housing 254 is threaded into the sealing Icollar 50 with extended, i.e., straight, threads and is secured by a lock nut 256, FIG. 4, threaded on the pump housing tube and seated against the sealing collar 59. With this construction the sealing "collar 50 may be rotated relative to the pump housing tube 54 to align the portions of the sealing collar 5) and the bottom shoe 56 into which the pipe 252 is threaded. Once this is done, the lock nut 256 is tightened to maintain the desired relative angular positions, and the desired axial spacing, of the sealing collar 5G and the bottom shoe 56.

As will be apparent, since relative rotation between the bottom shoe 56 and the sealing collar 50 must occur while the desired angular positions and axial spacing of these components are being established, yconnecting the parallel pipe 252 to the sealing collar 50 and the bottom shoe 56, or to at least one of them, must be done later. Also, there must be provision for axial movement of the pipe 252 relative -to one or the other of the sealing collar 50 and the bottom shoe 56 to permit threaded connections of the pipe 252 to both of these components.

The present invention solves the foregoing problems by dividing the pipe 252 into an upper section 258 and a lower section 260 with a telescoping connection or slip joint 262 therebetween. Referring to FIG. 5 of the drawings, threaded onto the upper end of the lower pipe section 260 is a coupling 264 having a stem 266 which is slidable in the upper pipe section 258 and which carries an O-ring 268 to provide a fluid tight seal therebetween. A gland nut 270 is threaded onto the coupling 264 and is provided with an internal annular ange 272 engageable with an external annular ange 274 on the upper pipe section 258.

With the foregoing construction, after the sealing collar 50 and the bottom shoe 56 have been locked in their proper relative positions, the telscoping connection 262 is contracted sufficiently to permit threading the upper and lower pipe sections 258 and 266 intothe sealing collar 50 and the bottom shoe 56, respectively, the telescopic connection extending as this is done. Alternatively, one of the pipe sections S and 266 is initially threaded into the corresponding component 56 or 56 of the bottom hole assembly 20 and the proper relative positions of the sealing collar 50 and the bottom shoe 56 are then established with the telscopic connection 262 contracted to permit the pipe section 258 to clear the sealing collar 56, or the pipe section 269 to clear the bottom shoe 56. Thereafter, if the pipe section 258 was initiaiy threaded into the sealing collar 50, the pipe section 260 is threaded into the bottom shoe 56, the telescopic connection 262 extending as this is done, In either case, once the pipe sections 258 and 260 are tightly -threaded into the sealing collar 50 and the bottom shoe 56 by means of the tapered pipe threads shown, the gland nut 270 is tightened to complete the installation. Thus, the telescopic connection 262 between the pipe sections 258 and 260 provides a simple means of connecting the pipe 252 to the sealing collar 5G and the bottom shoe 56 after the relative positions of these components of the bottom hole assembly 25 have been established. Also, the lgland nut 270 is tightened sufliciently to tension the pipe sections 25S and 260 to the extent necessary to prevent bowing of the pump housing tube 54 by `the bending moment produced by the column pressure within the pipe 252 acting on the bottom shoe 56, which is an important feature.

Although an exemplary embodiment of the present invention has been disclosed herein for purposes of illustration, it will be understood that various changes, modications and substitutions may be incorporated in such embodiment without departing from the spirit of the invention as defined by the claims which follow.

`What is claimed is:

l. In a bottom hole assembly for a fluid operated pump assembly', the combination of:

(a) two vertically spaced members;

(b) a tube extending between and threadedly interengaging each of said members;

(c) said tube being threadedly connected to at least one of said members with extended machine threadsV to permit varying the vertical spacing and relative angle positions of said members for axially aligning predetermined portions thereof;

(d) a pipe parallel to and spaced from said tube externally thereof and extending `between and threadedly connected to said predetermined portions;

(e) said pipe including upper and lower sections;

(f) connecting means providing a telescopic sliding connection between said pipe sections to permit varying the over-all length of said pipe; and

(g) means acting between said pipe sections for tensioning said pipe sections sufiiciently to prevent iiuid pressure within said pipe and acting on at least one of said members from bowing said tube.

2. A bottom hole assembly as dened in claim l, wherein said means for tensioning said pipe sections is incorporated in said connecting means.

3. in a lbottom hole assembly for a fluid operated pump assembly, the combination of:

(a) two vertically spaced members;

(b) a tube extending between and threadedly connected to said members;

(c) said tube being threadedly connected to at least one of said members with extended-threads;

(d) a pipe parallel to and spaced from said tube externally thereof and extending between and threadedly connected to said members;

(e) said pipe including upper and lower sections;

(f) connecting means providing a telescopio sliding connection between said pipe sections; and

(g) threaded means incorporated in said connecting :means for tensioning said pipe sections sufficiently to prevent'fluid pressure within said pipe and acting on at least one of said members from bowing said tube.

4. In a bottom hole assembly for a fluid operated pump assembly, the combination of z (a) two vertically spaced members;

(b) `a tube extending lbetween and threadedly connected to said members;

(c) said tube being threadedly connected to one of said lmembers with extended threads and to the other with tapered threads;

(d) a pipe parallel to and spaced from said tube externally thereof and extending between and threadedly connected to said members;

(e) said pipe including upper and lower sections;

(f) connecting means providing a telescopic sliding connection between said pipe sections; and

(g) threaded means incorporated in said connecting means for tensioning said pipe sections suiciently to prevent uid pressure within said pipe and acting on yat least one of said members from bowing said tube.

References Cited UNITED STATES PATENTS 1,710,937 4/1929 McCarthy 10s-233 2,304,394 12/1942 Biermann 285-132 Goode 285-354 Dale 285-302 Garrett 103-233 Coberly 103-4 Boydston 103-4 Coberly 103-4 Garrett 10S-233 Garrett 10S- 233 10 CARL W. TOMLIN, Primary Examiner.

E. C. ALLEN, Examiner.

R. GIANGIORGI, D. W. AROLA,

Assistant Examiners. 

1. IN A BOTTOM HOLE ASSEMBLY FOR A FLUID OPERATED PUMP ASSEMBLY, THE COMBINATION OF: (A) TWO VERTICALLY SPACED MEMBERS; (B) A TUBE EXTENDING BETWEEN AND THREADEDLY INTERENGAGING EACH OF SAID MEMBERS; (C) SAID TUBE BEING THREADEDLY CONNECTED TO AT LEAST ONE OF SAID MEMBERS WITH EXTENDED MACHINE THREADS TO PERMIT VARYING THE VERTICAL SPACING AND RELATIVE ANGLE POSITIONS OF SAID MEMBERS FOR AXIALLY ALIGNING PREDETERMINED PORTIONS THEREOF; (D) A PIPE PARALLEL TO AND SPACED FROM SAID TUBE EXTERNALLY THEREOF AND EXTENDING BETWEEN AND THREADEDLY CONNECTED TO SAID PREDETERMINED PORTIONS; (E) SAID PIPE INCLUDING UPPER AND LOWER SECTIONS; (F) CONNECTING MEANS PROVIDING A TELESCOPIC SLIDING CONNECTION BETWEEN SAID PIPE SECTIONS TO PERMIT VARYING THE OVER-ALL LENGTH OF SAID PIPE; AND (G) MEANS ACTING BETWEEN SAID PIPE SECTIONS FOR TENSIONING SAID PIPE SECTIONS SUFFICIENTLY TO PREVENT FLUID PRESSURE WITHIN SAID PIPE AND ACTING ON AT LEAST ONE OF SAID MEMBERS FROM BOWING SAID TUBE. 